Ok, I think the glue record will stay correct now. I finally got someone at GoDaddy ('Chad') who understood the problem and seems to have fixed it. BTW: RP emailed me privately with info on how to change a domain's authoritative name servers using GoDaddy's interface. I don't know why; I know how to do this, and there's been nothing wrong with the domain's authoritative name servers, per se, but Thanks. Also, MH from Verisign offered to take my call. Thanks for the offer. Thanks especially to William Leibzon, for giving just the right advice. I still have no understanding of what was causing the glue in the gTLD server to switch back and forth between correct and incorrect IPs, but Chad assured me things would be OK now. I'm tempted to try making one of the authoritative name servers for a toy domain www.<domain> to see what happens. Anyone tried it? I imagine this would result in slightly faster lookups, though the high TTL and propagation make it risky, and not appropriate for high availability sites. (I'm assuming the result would be that the query to the gTLD for the NS would also provide the answer for www, so no query to the domain's NS would be needed for the oh-so-common www lookup.)